Prediction of remaining implant life

Abstract

Devices, systems, and techniques are disclosed for predicting remaining life of medical devices. For example, a system may include an elongated member configured to be implanted within a patient, wherein the elongated member is configured to be coupled to an implantable medical device (IMD), the IMD configured to deliver therapy to the patient via the elongated member. The sensor may be carried by the elongated member and configured to provide a signal indicative of deformation experienced by the elongated member. The IMD may generate an alert indicative of predicted remaining device life and / or modify therapy delivery based on the signal indicative of deformation.

Description

PREDICTION OF REMAINING IMPLANT LIFETECHNICAL FIELD

[0001] This Application claims priority from U.S. Provisional Patent Application 63 / 516,440 filed 28 July 2023, the entire content of which is incorporated herein by reference.

[0002] The disclosure relates to medical devices and, more particularly, sensors for monitoring medical device usage.BACKGROUND

[0003] Implantable medical devices (IMDs) may be used to monitor a patient condition and / or deliver therapy to the patient. Example IMDs may be implanted to symptoms related to chronic pain, tremor, Parkinson's disease, multiple sclerosis, spinal cord injury, cerebral palsy, amyotrophic lateral sclerosis, dystonia, torticollis, epilepsy, pelvic floor disorders, gastroparesis, muscle stimulation (e.g., functional electrical stimulation (FES) of muscles) or obesity.

[0004] Currently implanted systems typically include multiple devices, such as an electrical stimulator connected to one or more leads or a drug pump connected to one or more catheters. The implant life of the any of these devices may be based on the battery life or component wear expectations. In some examples, patients may need to have surgery to replace one or more of the components of the implanted system in order to continue to receive monitoring or treatment.SUMMARY

[0005] In general, the disclosure is directed to devices, systems, and techniques for predicting or estimating the life of implantable medical devices (IMD) based on sensed data. A medical device, such as a catheter or medical lead, may include one or more sensors disposed along a portion of the implant that can be subject to strain and / or deformation while implanted within the patient. The sensor may be configured to sense the mechanical exposures of the implant during implant, such as flexing or bending. In addition, an IMD attached to or in communication with the implant s will be able to use the information from the one or more sensors to generate metrics related to implant remaining life, potentialoperational issues regarding the implant, etc. and generate an alert and / or modify therapy in response to the operational life of the implant predicted from the sensor data.

[0006] In some examples, the one or more sensors may be mounted to an external surface of the implanted device (e.g., the lead or catheter) or embedded within the implanted device. Each sensor may include a component configured to provide information regarding deformation or strain experienced by the implanted device. For example, the sensor may include a strain gauge or other mechanism that provides a signal indicative of deformation over time. In another example, the sensor may include a component that fractures or otherwise experiences a structural change after a predetermined number of deformations and / or a magnitude of deformation. This structural change may be configured to occur before or in advance of the implanted device failing such that this information can predict upcoming device failure. An IMD may use this information to generate an alert to a user for intervention and / or an adjustment to therapy delivery due to predicted end of life of the implanted device.

[0007] In one example, a system includes an elongated member configured to be implanted within a patient, wherein the elongated member is configured to be coupled to an implantable medical device (IMD), the IMD configured to deliver therapy to the patient via the elongated member; and a sensor carried by the elongated member and configured to provide a signal indicative of deformation experienced by the elongated member.

[0008] In another example, a method includes receiving, by processing circuitry, a signal from a sensor carried by an elongated member, wherein the elongated member is configured to be implanted within a patient and coupled to an implantable medical device (IMD) configured to deliver therapy to the patient via the elongated member, and wherein the signal is indicative of deformation experienced by the elongated member; and determining, by the processing circuitry and based on the signal, a functional life status for the elongated member implanted within the patient.

[0009] In another example, a computer-readable storage medium includes instructions that, when executed by processing circuitry, causes the processing circuitry to: receive a signal from a sensor carried by an elongated member, wherein the elongated member is configured to be implanted within a patient and coupled to an implantable medical device (IMD) configured to deliver therapy to the patient via the elongated member, and wherein the signal is indicative of deformation experienced by the elongated member; and determine, based on the signal, a functional life status for the elongated member implanted within the patient.BRIEF DESCRIPTION OF DRAWINGS

[0010] FIG. 1A, IB, and 1C are conceptual diagrams illustrating example medical device systems that include implantable medical devices coupled to implanted devices.

[0011] FIG. 2 is a block diagram illustrating an example configuration of components of an IMD, in accordance with one or more techniques of this disclosure.

[0012] FIG. 3 is a block diagram illustrating an example configuration of components of the external programmer of FIG. 1, in accordance with one or more techniques of this disclosure.

[0013] FIGS. 4 A and 4B are conceptual diagrams of example sensors configured to detect deformation via component fracture.

[0014] FIG. 5 is a conceptual diagram of an example sensor configured to generate a change in electrical signal in response to deformation.

[0015] FIGS. 6 A, 6B, and 6C are cross-sectional views of an exemplary lead with different locations for a deformation sensors.

[0016] FIG. 7 is a conceptual diagram of an example sensor and included energy source configured to detect deformation of a medical lead.

[0017] FIG. 8 is a flow diagram illustrating an example technique for sensing fracturing of the IMD and generating an alert, in accordance with one or more techniques of this disclosure.

[0018] FIG. 9 is a flow diagram illustrating an example technique for generating an alert in response to determining that cumulative deformation exceeds a deformation threshold, in accordance with one or more techniques of this disclosure.DETAILED DESCRIPTION

[0019] In general, this disclosure describes techniques for predicting the life of medical devices configured to implanted within a patient. Some medical devices have a relatively straightforward end of life prediction, such as a medical device that has a battery that eventually is depleted during operation. However, other medical devices that can be used until a mechanical component fails or degrades beyond operational parameters. These failures can include metal fracture, material plastic deformation, layer delamination, material degradation from the biological implant environment, or any other types of failures.

[0020] Therapy delivery components, such as a medical lead carrying electrodes or drug delivery catheter can be notoriously difficult to predict from an end of life perspective, bothaccurately and survivability after failure. In order to predict the lifespan of mechanical components, one can estimate a number of flexing cycles per year and determine the amount of time that the device can continue to function (e.g., a predetermined number of months or years). For example, if a catheter would be estimated to see 100,000 bends a year, a 700,000 bend device would meet a 7-year implant life expectation. However, each device experiences different events and frequency of movement in different patients which can render the implant device life expectancy inaccurate. Moreover, real-world tracking of device survival is infrequently tracked in order to match predicted life expectancy with actual device survival. Device failure while implanted can prevent the delivery of effective therapy or potentially subject the patient to tissue damage or more complicated device extraction.

[0021] As described herein, systems, devices and techniques may be configured to monitor mechanical exposure and predict the remaining life of an implanted device. For example, the implanted devices may include leads or catheters with one or more sensors configured to monitor deformation of the device over time. An IMD or other processing device may use the information from the sensors generate and track metrics related to the mechanical deformation over time or in response to a failure event. The IMD or other device may generate an alert indicative of the deformation or end of life or adjust therapy delivery in response to the deformation information.

[0022] In some examples, the addition of sensors on the IMDs may have the benefit of monitoring therapy efficacy, patient safety, warning signs of a failing therapeutic system, and incorporation into a feedback loop to automatically adjust therapy or provide recommendations for updates to therapy. For example, physiological metrics like breathing or patient motion could be monitored by the device sensors as well. In one example, if an increase in the breathing rate is known to be correlated with excessive therapy or increased rapid movements being a sign of insufficient therapy, then the system can use the deformation signals as feedback to control delivery of therapy and / or monitor patient health.

[0023] The sensors described herein may provide the added benefit of the system capability for monitoring therapy efficacy, patient safety, warning signs of a failing therapeutic system. The system may incorporate this sensed information into a feedback loop to automatically adjust therapy and / or provide recommendations for updates to therapy. For example, metrics like breathing or motion could plausibly be monitored by the implanted device sensors that detect deformation. If an increase in the breathing rate is known to be correlated with excessive therapy or increased rapid movements being a sign of insufficient therapy, then the system may be configured to change one or more parameters definingtherapy until the sensed information indicates that therapy may be effective, or no longer ineffective.

[0024] As described herein, there is an increased need for technology with the ability to predict remaining implant life more reliably based on actual conditions for the implanted device. By increasing the accuracy of implant life prediction using sensors described herein, the systems may be configured to increase safety for the patient via alarming or predicting failures that would otherwise manifest as a return of symptoms or other undesirable effects. In this manner, soon to be ineffective implanted devices can be replaced or accounted for before failure results in a negative outcome for the patient.

[0025] FIG. 1A, IB, and 1C are conceptual diagrams illustrating example medical device systems 10 A, 10B, and 10C (collectively, “medical device systems 10”) that include implantable medical devices coupled to implantable medical leads or catheters. In the example of FIG. 1 A, medical system 10A includes an IMD 14A configured to deliver therapy to and / or sensing physiological signals from brain 24 of patient 12A through electrodes 20A and 20B of lead 16A (which may include multiple leads). More particularly, IMD 14 A may track mechanical exposure via sensors (e.g., one or more sensors 220 A and 220B of FIG. 2) at one or more locations (or for one or more lengths) along lead 16 A. The tracking / monitoring and signals may be conducted between, or generated by, the sensor which may be located proximal of electrodes 20A and / or 20B, between electrodes, or at multiple locations.

[0026] As shown in FIG. 1A, medical device system 10A includes IMD 14A with lead 16A entering through cranium 26 and implanted within brain 24 of patient 12Ato deliver deep brain stimulation (DBS). One or more electrodes 20A or 20B at the distal end of one or more leads 16A provide electrical pulses to surrounding anatomical regions of brain 24 in a therapy that may alleviate a condition of patient 12 A. In some examples, more than one lead 16Amay be implanted within brain 24 of patient 12Ato stimulate multiple anatomical regions of the brain.

[0027] DBS may be used to treat dysfunctional neuronal activity in the brain which manifests as diseases or disorders such as Huntington’s Disease, Parkinson’s Disease, or movement disorders. The exact reasons why electrical stimulation therapy is capable of treating such conditions of the brain is unknown, but symptoms of these diseases can be lessened or eliminated with electrical stimulation therapy. Certain anatomical regions of brain 24 are responsible for producing the symptoms of such brain disorders. As one example, stimulating an anatomical region, such as the Substantia Nigra, in brain 24 mayreduce the number and magnitude of tremors experienced by patient 12 A. Other anatomical regions may include the subthalamic nucleus, globus pallidus interna, ventral intermediate, and zona inserta. Anatomical regions such as these are targeted by the clinician during the implantation of lead 16A. In other words, the clinician may attempt to position the distal portion of lead 16 A, including the one or more electrodes, as close to these regions as possible.

[0028] In the example of FIG. IB, system 10B may be similar to system 10A and includes an implantable medical device (IMD) 14 configured to deliver therapy to and / or sense physiological signals from target tissue. The target tissue may include or be near spinal cord 28 and / or pelvic nerves 6 (e.g., a pudendal nerve or sacral nerve), or any other nervous or muscle tissue that may be stimulated or from which physiological signals may be sensed of patient 12B through lead 16B. More particularly, IMD 14B may track mechanical exposure via sensors (e.g., one or more sensors 220A and 220B of FIG. 2) at one or more locations (or for one or more lengths) along lead 16B. The stimulation and signals may be conducted between the sensors and IMD 14B by conductors within lead 16B, which are electrically connected to IMD 14B by contacts at proximal end 18B of lead 16B. IMD 14B may provide neurostimulation to treat symptoms of patient 12B, such as pain, fecal or urinary incontinence, erectile dysfunction, or other sexual dysfunction.

[0029] In the example of FIG. 1C, system 10C may be similar to system 10A or 10B. However, IMD 14C is configured to deliver drug therapy to and / or sense physiological signals from target tissue. The target tissue may include or be near spinal cord 28 and / or pelvic nerves 6 (e.g., a pudendal nerve or sacral nerve), or any other nervous or muscle tissue that may benefit from drug delivery or from which physiological signals may be sensed of patient 12C through catheter 16C. More particularly, IMD 14C may track mechanical exposure via sensors (e.g., one or more sensors 220A and 220B of FIG. 2) at one or more locations (or for one or more lengths) along catheter 16B. IMD 14C may include a drug pump that forces fluid out of a fluid reservoir of IMD 14C and through catheter 16C and out of an outlet 20C in the distal end of catheter 16C. IMD 14C may provide neurostimulation to treat symptoms of patient 12C, such as pain, fecal or urinary incontinence, erectile dysfunction, or other sexual dysfunction.

[0030] HMDs 14 A, 14B, and 14C (collectively “IMDs 14”) may include electronics and other internal components necessary or desirable for providing the functionality described herein as being associated with the device. In one example, HMDs 14 include processing circuitry, memory, signal generation circuitry, sensing circuitry, telemetry circuitry, and apower source. In general, memory of an IMD 14 may include computer-readable instructions that, when executed by processing circuitry of the IMD, cause it to perform various functions attributed to the device herein. For example, processing circuitry of an IMD 14 may control the signal generation circuitry, pump control circuitry, and sensing circuitry according to instructions and / or data stored on memory to deliver therapy to patient 12, sense physiological signals of the patient, and perform other functions related to treating one or more conditions of the patient with IMD 14.

[0031] In any of systems 10A, 10B, and 10C, one or more leads 16A or 16B or catheter 16C may include one or sensors for monitoring mechanical exposure of the lead or catheter to deformation, strain, or other mechanical stresses that could reduce the operational life expectancy of the lead or catheter. In this manner, the system may use this sensed information from the lead or catheter to predict the remaining operational life of the lead or catheter due to mechanical exposure such as deformation. In one example, the system includes an elongated member (e.g., leads 16 A, 16B or catheter 16C or the housing or body thereof) configured to be implanted within a patient, wherein the elongated member is configured to be coupled to an IMD, such as one of IMD 14, where the IMD configured to deliver therapy to the patient via the elongated member. The system may also include a sensor (such as any of sensors 220 A or 220B of FIG. 2) carried by the elongated member and configured to provide a signal indicative of deformation experienced by the elongated member. The elongated member may be or include a medical lead comprising a plurality of electrodes configured to deliver electrical stimulation generated by the IMD. In other examples, the elongated member may be or include a catheter configured to deliver a fluid provided from the IMD.

[0032] In some examples, the sensor includes an electrically conductive element configured to fracture after a predetermined number of bending cycles associated with the deformation experienced by the elongated member. The predetermined number of bending cycles may be selected to be less than the number of bending cycles expected to cause fracture or other failure of operational components of the elongated member, such as conductors of the medical lead or structural wall of the catheter. In this manner, fracture of the conductive element of the sensor may predict upcoming failure of one or more other component of the elongated member.

[0033] In other examples, the sensor may be configured to vary an electrical characteristic of an electrical signal applied to the sensor during the deformation experienced by the elongated member. For example, a voltage may be applied to a strain sensingcomponent, such as a wheatstone bridge or other strain gauge, force sensor, deformation sensor that detects changes in distance along the sensor, or any other sensor. In some examples, the sensor may include a carbon film, carbon nanotubes in silicone to generate a voltage, or even just metal wire. The IMD or other device may monitor this change in the electrical sensor for determining cumulative and / or magnitudes of deformation that the IMD can then generate predictions of end of the useful life of the elongated member.

[0034] In some examples, the sensor for detecting mechanical exposure is carried on an outside surface of a lead body of the elongated member. In other examples, the sensor is embedded within a flexible polymer defining a lead body of the elongated member. In either case, the sensor may be configured to experience deformation and / or strain that the elongated member also experiences.

[0035] The IMD coupled to the elongated member may provide the operational power, such as a current and / or voltage so that the sensor can operate. In other examples, the sensor may use it’s own power. For example, a capacitor or other battery storage device may be carried on the elongated body and coupled to the components of the sensor. In some examples, the sensor includes a sensing circuit and an energy scavenging device configured to generate and store electrical power from movement of the elongated member to power the sensor and power the sensing circuit of the sensor using the electrical power. The energy scavenging device may generate a current in response to the bending of the elongated member, accelerations associated with body movement of the patient, or any other mechanism for generating a current for storing energy.

[0036] The IMD or other computing device may receive the signal from the sensor and determine, based on the signal, a functional life status for the elongated member implanted within the patient. As discussed above, the functional life status may be the predicted remaining functional life for the lead or catheter, for example, or may an indication of a percentage of full life or other indication of how long or how much the device can be used before it should be replaced may become non-functional. In some examples, the IMD may monitor signals from the sensor over time in order to determine a cumulative mechanical exposure that reduces the expected life. In other example, the received signal from the sensor may indicate planned sensor component failure due to mechanical exposure, and the IMD may apply a predicted amount of time or device usage remaining from that point of mechanical exposure.

[0037] As discussed above, an electrically conductive element of the sensor may be configured to fracture after a predetermined number of bending cycles associated withdeformation experienced or after some known mechanical exposure. Therefore, the signal received from the sensor may be configured to change in response to the fracture of the electrically conductive element. Then, the IMD or other device may determine the functional life status of the implanted device by determining that the signal has changed indicating the electrically conductive element has fractured.

[0038] In other examples, an electrical characteristic of the signal is configured to vary during the deformation experienced by the elongated member. For example, a strain gauge or other circuit may provide a changing electrical signal in response to deformation or strain. In this situation, the IMD may apply the signal to the sensor and sense the returning signal from the sensor to detect any changes due to mechanical exposure such as deformation. The IMD or other device may then determine the functional life status of the lead or catheter including the sensor by determining variation of the signal over time and determining the functional life status based on the variation of the signal over time.

[0039] In some examples, the IMD may take various actions based on the signal from the sensor. For example, the IMD may be configured to compare the functional life status to a threshold and determine that the functional life status does or does not exceed the threshold. In response to the functional life status exceeding the threshold, processing circuitry may control the IMD to at least one of: perform an integrity check on the elongated member or cease delivery of the therapy via the elongated member. These example actions may be triggered by the signal in the situation where the sensor signal may be indicative of a problem with the implanted device.

[0040] The IMD 14, external programmer 22, or other device may be configured to output the functional life status for display to a user. The functional life status may be presented via information such as how much longer the implanted device can be used before replacement, a prompt to adjust or terminate therapy, a request to schedule a clinician visit to replace the implanted device, or any other such information. In some examples, the functional life status may be presented as a numerical percentage, graphical portion, or some other indication of the proportion of time used, or remaining, for operation of the implanted device.

[0041] FIG. 2 is a block diagram illustrating an example configuration of components of an IMD 200. IMD 200 may be an example of any of IMDs 14. In the example shown in FIG.2, IMD 200 includes processing circuitry 210, storage device 212, stimulation generation circuitry 202, sensing circuitry 206, communication circuitry 308, sensor(s) controller 222, and power source 224. Sensor 220A and 220B on respective leads 230A and 230B maydetect deformation or other mechanical exposure to one or more portions of the respective leads. Storage device 212 may store computer-readable instructions that, when executed by processing circuitry 210, cause IMD 200 to perform various functions described herein.

[0042] In the example shown in FIG. 2, storage device 212 stores therapy stimulation programs 214 and deformation sensor data 216. Each stored therapy stimulation program defines a particular program of therapy in terms of respective values for electrical stimulation parameters, such as a stimulation electrode combination, electrode polarity, current or voltage amplitude, and, if the stimulation generation circuitry 202 generates and delivers stimulation pulses, the therapy programs may define values for a pulse width, and pulse rate of a stimulation signal. In examples when IMD 200 delivers electrical stimulation therapy on a cyclic basis (as compared to on demand), storage device 212 stores, e.g., as part of therapy stimulation programs 214, cycle parameter information, such as, on cycle time duration and off cycle duration. In some examples, the therapy programs may be stored as a therapy group, which defines a set of therapy programs with which stimulation may be generated. The stimulation signals defined by the therapy programs of the therapy group may be delivered together on an overlapping or non-overlapping (e.g., time-interleaved) basis.

[0043] Acceleration sensor 225 controlled by sensor controller 222 may measure and detect changes in acceleration. Acceleration sensor 225 may monitor and assess patient movement or motion-related parameters. The collected acceleration data may provide insights into a patients mobility, fall detection, rehabilitation progress, or other parameters. Acceleration sensor 225 output is processed within IMD 200 processing circuitry 210, which may include algorithms for activity recognition, event detection, or trend analysis. The processed data can be stored, transmitted wirelessly, or used to trigger specific responses or intervention within IMD 200.

[0044] Deformation sensor data 216 stored by storage device 212 can include information collected during mechanical exposures such as flexing or bending. For example, deformation sensor data 216 may include information representative of a fracture or other change with a component of one of sensors 220. In some examples, deformation sensor data 216 may include information representative of the change in sensors 220 signals over time which can track the cumulative deformations and / or magnitude of deformations that may affect the determination of the functional life status of leads 230. Greater deformation in one cycle of flexing may be responsible for larger amount of device life than smaller magnitudes of deformation during a single cycle.

[0045] Stimulation generation circuitry 202, under the processing circuitry 210 may be a single channel or multi-channel stimulation generator circuit. In particular, stimulation generation circuitry 202 may be capable of delivering, a single stimulation pulse, multiple stimulation pulses or continuous signal at a given time via a single electrode combination or multiple stimulation pulses at a given time via multiple electrode combinations. In some examples, however, stimulation generator 202 may be configured to deliver multiple channels on a time-interleaved basis. For example, Accordingly, in some examples, stimulation generation circuitry 202 generates electrical stimulation signals in accordance with the electrical stimulation parameters noted above. Other ranges of stimulation parameter values may also be useful and may depend on the target stimulation site within patient 12A. While stimulation pulses are described, stimulation signals may be of any form, such as continuous-time signals (e.g., sine waves) or the like. Switch circuitry 204 may include one or more switch arrays, one or more multiplexers, one or more switches (e.g., a switch matrix or other collection of switches), or other electrical circuitry configured to direct stimulation signals from stimulation generation circuitry 202 to one or more of electrodes 232, 234, or directed sensed signals from one or more of electrodes 232, 234 to sensing circuitry 206. In other examples, stimulation generation circuitry 202 and / or sensing circuitry 206 may include sensing circuitry to direct signals to and / or from one or more of electrodes 232, 234, which may or may not also include switch circuitry 204.

[0046] Sensor controller 222 may be configured to monitor the signals from sensors 220. In some examples, sensor control 222 may receive the signals via sensing circuitry 206 to sense mechanical exposures of the IMD implanted in patient 12 A. In other examples, sensor controller 222 may directly receive electrical signals from sensors 220.

[0047] Sensing circuitry 206 monitors signals from any combination of electrodes 232, 234. In some examples, sensing circuitry 206 includes one or more amplifiers, filters, and analog-to-digital converters. Sensing circuitry 206 may be used to sense physiological signals, such as ECAPs. Additionally, or alternatively, sensing circuitry 206 may sense one or more stimulation pulses delivered to patient 105 via electrodes 232, 234. In some examples, sensing circuitry 206 detects electrical signals, such as stimulation signals and / or ECAPs from a particular combination of electrodes 232, 234. In some cases, the particular combination of electrodes for sensing ECAPs includes different electrodes than a set of electrodes 232, 234 used to deliver stimulation pulses. Alternatively, in other cases, the particular combination of electrodes used for sensing ECAPs includes at least one of the same electrodes as a set of electrodes used to deliver stimulation pulses to patient 105. Sensingcircuitry 206 may provide signals to an analog-to-digital converter, for conversion into a digital signal for processing, analysis, storage, or output by processing circuitry 210.

[0048] Communication circuitry 208 supports wireless communication between IMD 200 and an external programmer 22 or another computing device under the control of the processing circuitry 210. Processing circuitry 206 of IMD 200 may receive, as updates to programs, values for various stimulation parameters such as amplitude and electrode combination, from programmer 14 via communication circuitry 208. The updates to the therapy programs may be stored within therapy stimulation programs 214 portion of storage device 212. Communication circuitry 208 in IMD 200, as well as communication circuitries in other devices and systems described herein, such as programmer 14, may accomplish communication by RF communication techniques. In addition, communication circuitry 208 may communicate with external medical device programmer 14 via proximal inductive interaction of IMD 200 with programmer 14. Accordingly, communication circuitry 208 may send information to external programmer 14 on a continuous basis, at periodic intervals, or upon request from IMD 200 or programmer 14. For example, processing circuitry 210 may transmit deformation sensor data 216 to programmer 14 via communication circuitry 208.

[0049] Power source 224 is configured to deliver operating power to various components of IMD 16. Power source 224 may include, for example, a small rechargeable or non- rechargeable battery and a power generation circuit to produce the operating power. Recharging may be accomplished through proximal inductive interaction between an external charger and an inductive charging coil within IMD 200. In some examples, power requirements may be small enough to allow IMD 200 to utilize patient motion and implement a kinetic energy-scavenging device to trickle charge a rechargeable battery. In other examples, traditional batteries may be used for a limited period of time.

[0050] FIG. 3 is a block diagram illustrating an example configuration of components of the external programmer 22 of FIG. 1, in accordance with one or more techniques of this disclosure. External programmer 22 includes storage device 354, processing circuitry 352, communication circuitry 358, user interface 356, and power source 350. IMD may include sensors that capture physiological data or signals from the patient’s body.

[0051] Storage device 354 stores data and parameters necessary for the IMD’s operation, including patient-specific information, firmware, and configuration settings. Storage device 354 may include instructions for operating user interface 356 and processing circuitry 352, communication circuitry 358 and for managing power source 350. Storage device 354 may also store any therapy data retrieved from IMD 200, such as, but not limited to, brain activityinformation. The clinician may use this therapy data to determine the progression of the patient condition in order to plan future treatment for the disorder (or patient symptoms) of patient 12A. Storage device 354 may include any volatile or nonvolatile memory, such as RAM, ROM, EEPROM or flash memory. Storage device 354 may also include a removable memory portion that may be used to provide memory updates or increases in memory capacities. A removable memory may also allow sensitive patient data to be removed before programmer 14A is used by a different patient.

[0052] Processing circuitry 352 may analyze and interpret the signals acquired from sensors, performing computations, and controlling the device’s operations. Processing circuitry 352 may include any one or more of a microprocessor, a controller, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field-programmable gate array (FPGA), discrete logic circuitry, or any other processing circuitry configured to provide the functions attributed to processing circuitry 210 herein may be embodied as firmware, hardware, software, or any combination thereof. Processing circuitry 210 controls stimulation generation circuitry 202 to generate stimulation signals according to therapy stimulation programs 214 and deformation sensor data 216 stored in storage device 212 to apply stimulation parameter values specified by one or more of programs, such as amplitude, pulse width, pulse rate, and pulse shape of each of the stimulation signals. Processing circuitry 352 may be configured to present information in the form of numbers, text, or graphics that represent deformation sensor data or the functional life status of one or more implanted devices.

[0053] Communication circuitry 358 is coupled to the processing circuitry 352. Communication circuitry 358 enables bidirectional communication between the IMD and external devices, such as programmers or monitoring systems, facilitating data exchange, programming updates, and remote monitoring. Communication circuitry 358 supports wireless communication between IMD 200 and an external programmer 22 or another computing device under the control of processing circuitry 352. Processing circuitry 352 of programmer 22 may receive, as updates to programs, values for various stimulation parameters such as amplitude and electrode combination, from the external programmer via communication circuitry 208. Updates to the therapy stimulation programs 214 and deformation sensor data 216 may be stored within storage device 354. Communication circuitry 358 in programmer 22, as well as communication circuits in other devices and systems described herein, such as the external programmer, may accomplish communication by radiofrequency (RF) communication techniques. In addition, communication circuitry 358may communicate with IMD 200 via proximal inductive interaction. Communication circuitry 208 of IMD 200 may send information to the external programmer on a continuous basis, at periodic intervals, or upon request from IMD 200 or the external programmer.

[0054] A user, such as a clinician or patient 12 A, may interact with programmer 22 through user interface 356. User interface 356 includes a display (not shown), such as a LCD or LED display or other type of screen, to present information related to the therapy, such as information related to bioelectrical signals. User interface 356 is coupled to the processing circuitry 352. User interface 356 may provide the means for interaction between the patient and the IMD 200, allowing access to information or control certain functions. In addition, user interface 356 may include an input mechanism to receive input from the user. The input mechanisms may include, for example, buttons, a keypad (e.g., an alphanumeric keypad), a peripheral pointing device or another input mechanism that allows the user to navigate through user interfaces presented by processor 352 of programmer 22 and provide input.

[0055] As discussed above, if programmer 22 includes buttons and a keypad, the buttons may be dedicated to performing a certain function, or the buttons and the keypad may be soft keys that change function depending upon the section of the user interface currently viewed by the user. In addition, or instead, the screen (not shown) of programmer 22 may be a touch screen that allows the user to provide input directly to the user interface shown on the display. The user may use a stylus or their finger to provide input to the display. In other examples, user interface 86 also includes audio circuitry for providing audible instructions or sounds to patient 12A and / or receiving voice commands from patient 12A, which may be useful if patient 12A has limited motor functions. Patient 12, a clinician or another user may also interact with programmer 22 to manually select therapy programs, generate new therapy programs, modify therapy programs through individual or global adjustments, and transmit the new programs to IMD 200.

[0056] In some examples, dedicated keys within user interface 356 may be associated with a particular symptom. Patient 12A initiate the delivery of stimulation to alleviate a symptom simply by pressing the key associated with the particular symptom. In some examples, processing circuitry 352 may limit the number of times stimulation may be provided within a certain time frame in response to patient input.

[0057] Power source 350 is configured to deliver operating power to the components of programmer 22. Power source 350 may include a battery and a power generation circuit to produce the operating power. In some examples, the battery may be rechargeable to allow extended operation. Recharging may be accomplished by electrically coupling power source350 to a cradle or plug that is connected to an alternating current (AC) outlet. In addition, recharging may be accomplished through proximal inductive interaction between an external charger and an inductive charging coil within programmer 22. In other examples, traditional batteries (e.g., nickel cadmium or lithium-ion batteries) may be used. In addition, programmer 22 may be directly coupled to an alternating current outlet to operate. Power source 350 may include circuitry to monitor power remaining within a battery. In this manner, user interface 356 may provide a current battery level indicator or low battery level indicator when the battery needs to be replaced or recharged. In some cases, power source 350 may be capable of estimating the remaining time of operation using the current battery.

[0058] FIGS. 4 A and 4B are conceptual diagrams of example sensors 406 and 422 configured to detect deformation via component fracture. As shown in the example of FIG. 4A, lead 400 is an example implanted device and may be similar to any leads (e.g., leads 16 A, 16B or 230), but may be a catheter in other examples. Lead 400 includes elongated member 402 (e.g., a body or housing of lead 400) that carries electrodes 404 disposed on a distal end of lead 400.

[0059] Sensor 406 may be configured to detect deformation of lead 400 via eventual planned component fracture of electrically conductive element 410 contained within sensor 406. Electrically conductive element 410 may be electrically coupled to proximal contacts via conductors 408. In this manner, an IMD, such as IMD 200, may transmit an electrical signal through conductors 408 and electrically conductive element 410. Electrically conductive element 410 may be constructed with a selected material and dimensions (e.g., cross-sectional area, width, thickness, length, etc.) that may be configured to fracture after a predetermined amount of mechanical exposure, such as a predetermined amount of deformation, stress, strain, etc. This predetermined amount that causes fracture may be selected to occur prior to the failure of any other components of lead 400 and used as a predictor of functional life status of lead 400.

[0060] The example of FIG. 4B includes lead 420 that may be substantially similar to lead 400. However, sensor 422 may utilize a single loop of conductors 422 that itself is or includes an electrically conductive element constructed with a selected material and dimensions (e.g., cross-sectional area, width, thickness, length, etc.) that may be configured to fracture after a predetermined amount of mechanical exposure, such as a predetermined amount of deformation, stress, strain, etc. In this manner, fracture of any portion of conductors 422 may indicate that the functional life status of lead 420 is nearing an end.

[0061] In some examples, leads 400 or 420 may include multiple different sensors at different axial locations along the length of elongated member 402 and / or different circumferential locations around the perimeter of elongated member 402. This separate sensors may be serially connected to each other for power or separately and individually connected to IMD 200. Different sensors 406 or 422 may be used to monitor deformation that can occur at different locations of the respective lead 400 or lead 420. In other examples, different sensors 406 or 422 may be configured to fracture after different magnitudes of deformation over time as progressive indicators of the functional life status. For example, different sensors may use conductive elements of different materials and / or different dimensions in order to fracture after different amounts of mechanical exposure. IMD 200 may then update the functional life status after each sensor indicates fracture occurred. Sensors 406 and 422 may be disposed on the outer surface of elongated member 402 and / or within elongated member 402.

[0062] FIG. 5 is a conceptual diagram of an example sensor 510 configured to generate a change in electrical signal in response to deformation. As shown in the example of FIG. 5, lead 500 is an example implanted device and may be similar to any leads (e.g., leads 16A, 16B or 230), but may be a catheter in other examples. Lead 500 includes elongated member 402 (e.g., a body or housing of lead 400) that carries electrodes 404 disposed on a distal end of lead 400.

[0063] Sensor 510 may be configured to detect deformation of lead 500 via changes in an electrical signal output by sensor 510 in response to mechanical exposure such as deformation, bending, strain, stress, etc. For example, sensor 510 may include one or more wheatstone bridges or other strain gauges, flexible conductors that change resistance with elastic deformation, optical sensors that measure changes in distance, or any other type of sensing device connected to IMD 200 via conductors 508. Other example sensors may include a force sensor, a carbon film, carbon nanotubes in silicone to generate a voltage, or even just metal wire that may change an electrical property in response to mechanical changes such as bending, flexing, strain. IMD 200 may then determine a functional life status of lead 500 by monitoring the deformation other time, such as a number of bending cycles, magnitude of bending, stretching, and / or strain. These metrics from the deformation data can be compared to one or more thresholds in order to generate the functional life status that may represent the amount of time or other usage of lead 500.

[0064] In some examples, lead 500 may include multiple different sensors 510 at different axial locations along the length of elongated member 402 and / or differentcircumferential locations around the perimeter of elongated member 402. This separate sensors may be serially connected to each other for power or separately and individually connected to IMD 200. Different sensors 510 may be used to monitor deformation that can occur at different locations of lead 500. Sensors 510 may be disposed on the outer surface of elongated member 402 and / or within elongated member 402.

[0065] FIGS. 6 A, 6B, and 6C are cross-sectional views of an exemplary lead with different locations for a deformation sensor 608. Lead 600 may represent the cross-sectional views of any of leads 16A, 16B, 230, 400, 420, or 500. The placement of sensor 608 (e.g., sensor 406 or 422) may also apply to catheters configured to deliver a drug to the patient from a drug pump. As shown in FIG. 6A, lead 600 includes lead body 602 (or elongated member), electrodes 604, coiled conductors 606, and sensor 608. Electrodes 604 are ring electrodes disposed on the outer surface of lead body 110 and are electrically connected to coiled conductor 606. In particular, each electrode 604 is electrically connected to a wire of coiled conductor 606, and each wire may spin off from the coiled conductor at any location around the circumference of lead 600 to allow conduits and / or a stylet to pass to the distal portion of lead body 602. In some embodiments, coiled conductor 606 may not be in a coiled configuration.

[0066] Sensor 608 may be disposed within lead body 602 as shown in FIG. 6B which is a cross section of lead 600 at plane A in FIG. 6A. Longitudinal axis 612 may run through the center of lead body 602. Coiled conductors 606 are coiled around longitudinal axis 612 but radially inward from the placement of conductors 610 of sensor 608. Conductors 610 may thus be embedded within the polymer or other material used for lead body 602. Conductors 610 may generally run parallel to longitudinal axis 612, but may deviate in certain directions as needed to accommodate other features of lead 600.

[0067] FIG. 6C illustrates an example lead 630 that is substantially similar to lead 600. The cross-sectional view of FIG. 6C is taken from the plane A of FIG. 6 A. However, sensor 630 that includes conductors 640 may be disposed on the outer surface of lead body 602. Conductors 640 may include an insulative sheath or other element that electrically isolates the conductor from the patient. In some examples, the conductors on the outer surface of lead body 602 may include nanotubes that may be adhered to or painted onto the lead body surface. In some examples, these conductors on the lead body surface may be in electrical contact with a passive set screw or other electrical contact on the IMD that can be coupled to the conductors.

[0068] FIG. 7 is a conceptual diagram of an example sensor 706 and included energy source configured to detect deformation of a medical lead. As shown in the example of FIG. 7, lead 700 is an example implanted device and may be similar to any leads (e.g., leads 16A, 16B or 230), but may be a catheter in other examples. Lead 700 includes elongated member 702 (e.g., a body or housing of lead 700) that carries electrodes 704 disposed on a distal end of lead 700.

[0069] Sensor 706 may be configured to detect deformation of lead 700 via changes in an electrical signal output fracture due to deformation. Sensor 706 includes conductors 714 that can be used to fracture after a predetermined number of bending cycles or other mechanical exposure similar to sensor 422. However, sensor 706 may alternatively operate to generate varying signals such as sensor 510. Sensor 706 may operate from a separate power source such as an energy harvesting power source 708. Energy harvesting power source 708 may generate an electrical current caused by bending or other deformation of lead body 702 and store the energy in a battery or capacitor. That energy stored within energy harvesting power source 708 may be applied to operate processing circuitry 710 that processes signals from conductors 714 indicative of deformation. Processing circuitry 710 may also control antenna 712 to transmit the deformation data to IMD 200 wirelessly since sensor 706 is not in wired connection to IMD 200. In some examples, processing circuitry 710 may monitor the signals from conductors 714 and generate the deformation data and / or generate the functional life status of lead 700 from the deformation data. In other examples, IMD 200 or other device may receive the deformation data and determine a functional life status of lead 500 by monitoring for fracture of conductors 714 or other events such as deformation other time, such as a number of bending cycles, magnitude of bending, stretching, and / or strain. These metrics from the deformation data can be compared to one or more thresholds in order to generate the functional life status that may represent the amount of time or other usage of lead 700.

[0070] In some examples, lead 700 may include multiple different sensors 706 at different axial locations along the length of elongated member 702 and / or different circumferential locations around the perimeter of elongated member 702. This separate sensors may be connected to each other for power (e.g., to utilize one energy harvesting power source for multiple different deformation sensors) or operate separately. Different sensors 706 may be used to monitor deformation that can occur at different locations of lead 700. Sensors 706 may be disposed on the outer surface of elongated member 702 and / or within elongated member 702. Since sensor 706 may be self-contained with included energysources, sensor 706 may be attached to the outer surface of lead 700 as needed in order to obtain the deformation data for generation of the functional life status of lead 700.

[0071] FIG. 8 is a flow diagram illustrating an example technique for sensing fracturing of the IMD and generating an alert, in accordance with one or more techniques of this disclosure. In the example of FIG. 8, IMD 200 and processing circuitry 210 will be described as performing the functions, but other processing circuitry from other devices may partially or fully perform the functions in other examples.

[0072] Processing circuitry 210 may control IMD 200 to deliver therapy to patient 12A using IMD 200 (800). Processing circuitry 210 may receive sensor signals from the deformation sensor, such as sensors 220 (802). These sensor signals may provide binary information (e.g., intact or fractured conductor) associated with the deformation sensor. If the sensor signal does not indicate fracture (“NO” branch of block 804), processing circuitry 210 may continue to delivery therapy and receive additional signals from sensors 220 (800).

[0073] However, if processing circuitry 210 determines that the sensor signal does indicate a fracture within the sensor (“YES” branch of block 804), processing circuitry 210 can generate and send an alert to the user that the functional life status has changed and indicates that a certain amount of life has been used or that a certain operational lifetime remains for lead 230 (806). Processing circuitry 210 may control communication circuitry 208 to communicate the functional life status to programmer 22. In addition, or alternatively, processing circuitry 210 may adjust one or more parameters that define therapy and / or terminate therapy completely in response to the functional life status indicating that lead 230 is no longer fit for providing therapy.

[0074] FIG. 9 is a flow diagram illustrating an example technique for generating an alert in response to determining that cumulative deformation exceeds a deformation threshold, in accordance with one or more techniques of this disclosure. In the example of FIG. 9, IMD 200 and processing circuitry 210, and lead 500, will be described as performing the functions, but other processing circuitry from other devices may partially or fully perform the functions in other examples.

[0075] Processing circuitry 210 may control IMD 200 to deliver therapy to patient 12A using IMD 200. Processing circuitry 210 may receive and monitor sensor signals from the deformation sensor, such as sensor 510 (900). These sensor signals may indicate changes in an electrical signal output by sensor 510 in response to mechanical exposure such as deformation, bending, strain, stress, etc. For example, sensor 510 may include one or more wheatstone bridges or other strain gauges, flexible conductors that change resistance withelastic deformation, optical sensors that measure changes in distance, or any other type of sensing device connected to IMD 200 via conductors. Processing circuitry 210 may determine a cumulative deformation metric that indicates the amount of deformation that lead 500 has been subjected to during implantation (902).

[0076] Processing circuitry 210 may then compare the cumulative deformation to a deformation threshold (904). If the cumulative deformation does not exceed the deformation threshold (“NO” branch of block 906), processing circuitry 210 may continue to monitor the signals from the deformation sensor 510 (900). However, if processing circuitry 210 determines that the cumulative deformation does exceed the deformation threshold (“YES” branch of block 906), processing circuitry 210 can generate and send an alert to the user that the functional life status has changed and indicates that a certain amount of life has been used or that a certain operational lifetime remains for lead 500 (908). Processing circuitry 210 may control communication circuitry 208 to communicate the functional life status to programmer 22. In addition, or alternatively, processing circuitry 210 may adjust one or more parameters that define therapy and / or terminate therapy completely in response to the functional life status indicating that lead 230 is no longer fit for providing therapy.

[0077] In some examples, processing circuitry 210 may compare the cumulative deformation to multiple different thresholds or enter the cumulative deformation into a formula to generate a more precise functional life status for lead 500. For example, the cumulative deformation may be divided by an expected maximum lifetime deformation for lead 500 in order to generate a percentage of life used by lead 500. The inverse of that percentage may provide the percentage remaining of life of lead 500. Processing circuitry 210 may monitor multiple sensors 510 from the same implanted device (e.g., a single lead or catheter), and the most deformation experienced by the sensor may control the functional life status for lead 500 in some examples.

[0078] The deformation sensors described herein have generally been described as providing data related to the remaining operational life of the lead. However, in some examples, systems may also, or alternatively, monitor one or more physiological or anatomical parameters based on the determined deformation of the implanted device (e.g., lead or catheter). For example, IMD 200 may be configured to monitor breathing, cardiac metrics based on pulsatile flow caused deformation, patient activity, bladder fill cycles, patient falls, or any other patient functions. IMD 200 may adjust therapy parameters based on this deformation data before any device failure is even predicted.

[0079] The following examples are described herein.

[0080] Example 1. A system comprising: elongated member configured to be implanted within a patient, wherein the elongated member is configured to be coupled to an implantable medical device (IMD), the IMD configured to deliver therapy to the patient via the elongated member; and a sensor carried by the elongated member and configured to provide a signal indicative of deformation experienced by the elongated member.

[0081] Example 2. The system of example 1, wherein the elongated member is a medical lead comprising a plurality of electrodes configured to deliver electrical stimulation generated by the IMD.

[0082] Example 3. The system of any of examples 1 and 2, wherein the elongated member is a catheter configured to deliver a fluid provided from the IMD.

[0083] Example 4. The system of any of examples 1 through 3, wherein the sensor comprises an electrically conductive element configured to fracture after a predetermined number of bending cycles associated with the deformation experienced by the elongated member.

[0084] Example 5. The system of any of examples 1 through 4, wherein the sensor is configured to vary an electrical characteristic of an electrical signal applied to the sensor during the deformation experienced by the elongated member.

[0085] Example 6. The system of any of examples 1 through 5, wherein the sensor is carried on an outside surface of a lead body of the elongated member.

[0086] Example 7. The system of any of examples 1 through 6, wherein the sensor is embedded within a flexible polymer defining a lead body of the elongated member.

[0087] Example 8. The system of any of examples 1 through 7, wherein the sensor comprises a sensing circuit and an energy scavenging device configured to:

[0088] generate and store electrical power from movement of the elongated member to power the sensor; and power the sensing circuit of the sensor using the electrical power.

[0089] Example 9. The system of any of examples 1 through 8, further comprising the IMD, wherein the IMD comprises processing circuitry configured to: receive the signal from the sensor; determine, based on the signal, a functional life status for the elongated member implanted within the patient.

[0090] Example 10. The system of example 9, wherein the IMD comprises stimulation generation circuitry configured to generate electrical stimulation therapy deliverable by electrodes carried by the elongated member, and wherein the sensor is distinct from the electrodes.

[0091] Example 11. A method comprising: receiving, by processing circuitry, a signal from a sensor carried by an elongated member, wherein the elongated member is configured to be implanted within a patient and coupled to an implantable medical device (IMD) configured to deliver therapy to the patient via the elongated member, and wherein the signal is indicative of deformation experienced by the elongated member; and determining, by the processing circuitry and based on the signal, a functional life status for the elongated member implanted within the patient.

[0092] Example 12. The method of example 11, wherein the signal is configured to change in response to an electrically conductive element configured to fracture after a predetermined number of bending cycles associated with the deformation experienced by the elongated member, and wherein determining the functional life status comprises determining that the signal has changed indicating the electrically conductive element has fractured.

[0093] Example 13. The method of any of examples 11 and 12, wherein an electrical characteristic of the signal is configured to vary during the deformation experienced by the elongated member, and wherein determining the functional life status comprises determining variation of the signal over time and determining the functional life status based on the variation of the signal over time.

[0094] Example 14. The method of any of examples 11 through 13, further comprising applying an electrical signal to the sensor, and wherein the signal is indicative of a change to the electrical signal indicative of the deformation.

[0095] Example 15. The method of any of examples 11 through 14, further comprising outputting, by the processing circuitry, the functional life status for display to a user.

[0096] Example 16. The method of any of examples 11 through 15, further comprising: comparing the functional life status to a threshold; determining that the functional life status exceeds the threshold; and responsive to the functional life status exceeding the threshold, controlling the IMD to at least one of: perform an integrity check on the elongated member or cease delivery of the therapy via the elongated member.

[0097] Example 17. The method of any of examples 11 through 16, further comprising controlling delivery of therapy to the patient via the elongated member.

[0098] Example 18. The method of example 17, wherein the elongated member is a medical lead comprising a plurality of electrodes, and wherein controlling delivery of therapy comprises controlling the IMD to deliver electrical stimulation therapy via a subset of the plurality of electrodes.

[0099] Example 19. The method of example 17, wherein the elongated member is a catheter configured to deliver a fluid from the IMD, and wherein controlling delivery of therapy comprises controlling the IMD to deliver a fluid to the patient via the catheter.

[0100] Example 20. A computer-readable storage medium comprising instructions that, when executed by processing circuitry, causes the processing circuitry to: receive a signal from a sensor carried by an elongated member, wherein the elongated member is configured to be implanted within a patient and coupled to an implantable medical device (IMD) configured to deliver therapy to the patient via the elongated member, and wherein the signal is indicative of deformation experienced by the elongated member; and determine, based on the signal, a functional life status for the elongated member implanted within the patient.

[0101] The techniques described in this disclosure may be implemented, at least in part, in hardware, software, firmware or any combination thereof. For example, various aspects of the described techniques may be implemented within one or more processors, such as fixed function processing circuitry and / or programmable processing circuitry, including one or more microprocessors, digital signal processors (DSPs), application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), or any other equivalent integrated or discrete logic circuitry, as well as any combinations of such components. The term “processor” or “processing circuitry” may generally refer to any of the foregoing logic circuitry, alone or in combination with other logic circuitry, or any other equivalent circuitry. A control unit comprising hardware may also perform one or more of the techniques of this disclosure.

[0102] Such hardware, software, and firmware may be implemented within the same device or within separate devices to support the various operations and functions described in this disclosure. In addition, any of the described units, modules or components may be implemented together or separately as discrete but interoperable logic devices. Depiction of different features as modules or units is intended to highlight different functional aspects and does not necessarily imply that such modules or units must be realized by separate hardware or software components. Rather, functionality associated with one or more modules or units may be performed by separate hardware or software components, or integrated within common or separate hardware or software components.

[0103] The techniques described in this disclosure may also be embodied or encoded in a computer-readable medium, such as a computer-readable storage medium, containing instructions. Instructions embedded or encoded in a computer-readable storage medium may cause a programmable processor, or other processor, to perform the method, e.g., when theinstructions are executed. Computer readable storage media may include random access memory (RAM), read only memory (ROM), programmable read only memory (PROM), erasable programmable read only memory (EPROM), electronically erasable programmable read only memory (EEPROM), flash memory, a hard disk, a CD-ROM, a floppy disk, a cassette, magnetic media, optical media, or other computer readable media.

[0104] Various examples have been described. These and other examples are within the scope of the following claims.

Claims

WHAT IS CLAIMED IS:

1. A system comprising: elongated member configured to be implanted within a patient, wherein the elongated member is configured to be coupled to an implantable medical device (IMD), the IMD configured to deliver therapy to the patient via the elongated member; and a sensor carried by the elongated member and configured to provide a signal indicative of deformation experienced by the elongated member.

2. The system of claim 1, wherein the elongated member is a medical lead comprising a plurality of electrodes configured to deliver electrical stimulation generated by the IMD.

3. The system of any of claims 1 and 2, wherein the elongated member is a catheter configured to deliver a fluid provided from the IMD.

4. The system of any of claims 1 through 3, wherein the sensor comprises an electrically conductive element configured to fracture after a predetermined number of bending cycles associated with the deformation experienced by the elongated member.

5. The system of any of claims 1 through 4, wherein the sensor is configured to vary an electrical characteristic of an electrical signal applied to the sensor during the deformation experienced by the elongated member.

6. The system of any of claims 1 through 5, wherein the sensor is carried on an outside surface of a lead body of the elongated member.

7. The system of any of claims 1 through 6, wherein the sensor is embedded within a flexible polymer defining a lead body of the elongated member.

8. The system of any of claims 1 through 7, wherein the sensor comprises a sensing circuit and an energy scavenging device configured to: generate and store electrical power from movement of the elongated member to power the sensor; and power the sensing circuit of the sensor using the electrical power.

9. The system of any of claims 1 through 8, further comprising the IMD, wherein the IMD comprises processing circuitry configured to: receive the signal from the sensor; and determine, based on the signal, a functional life status for the elongated member implanted within the patient.

10. The system of claim 9, wherein the IMD comprises stimulation generation circuitry configured to generate electrical stimulation therapy deliverable by electrodes carried by the elongated member, and wherein the sensor is distinct from the electrodes.

11. A computer-readable storage medium comprising instructions that, when executed by processing circuitry, causes the processing circuitry to perform the functions of any of claims 1 through 10.

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